630 THE BUILDING FOR THE LIBEARY OF CONGRESS. 



60-liorsepower horizontal shell tubular boilers, and a coal storage 

 capacity of 3,000 tons. The steam operates the hydraulic pumps for 

 elevator power and water supply, the air compressor for the pneu- 

 matic-tube system, and the dynamo engines for electric lighting and 

 power apparatus, the exhaust from which is passed through eight sets 

 of tubular tanks for heating the water required for warming the 

 building. By circulation of this hot water through cast-iron coils of 

 3-inch pipe, inclosed in chambers of brick distributed throughout the 

 cellar, to which it is carried and returned by pipes, fresh air from 

 outside the building is warmed and passed by natural draft up wall 

 flues to the respective stories and apartments above. The air thus 

 taken into the building and circulated through the rooms is discharged 

 at the roof through other wall flues, 



A complete system of electric lighting is provided for night service, 

 including both the building and surrounding grounds; also means of 

 internal communication between all parts of the building through 

 cables of electric wires laid in the floors, with frequent points for 

 access and connection without disturbing the permanent structure. 



The foundations of the building are of hydraulic cement concrete, 

 6 feet deep in ground which is a mixture of clay and sand of very 

 uniform character. The cellar walls are of hard red biick; the exte- 

 rior face of the superstructure of a fine grained light blue granite from 

 Concord, I^. H. ; the stone of the rotunda and the trimmings of the 

 court walls a light blue granite from near Woodstock, Md. ; the facing 

 of the court walls enameled brick from Leeds, England; and the back- 

 ing and interior walls as well as all of the vaulting of the basement 

 and first stories are of hard red brick. Most of the floors that are flat 

 ceiled are of terra cotta, and this material also forms the covering and 

 filling of the roofs and main dome, of which the supporting members 

 are of rolled steel in beams, girders, and trusses. All of the floors are 

 leveled up with concrete and surfaced with tiles, terrazzo, or mosaic in 

 the public spaces, while in the office and working rooms they are covered 

 with a carpet of southern pine boards. 



The most important of the strictly useful features of the building are 

 the book stacks, of which the design is largely original. The problem 

 was new, not only through the capacity to be provided but the numer- 

 ous other conditions to be met, such as light, ventilation, adjustability 

 to several uses, communication, immunity from fire, cleanliness, dura- 

 bility, and simplicity. It was also necessary that rapid mechanical 

 transmission of books between the shelving and the reading room 

 should be provided, coupled with a quick and reliable means of com- 

 munication, both written and oral. Existing libraries lacked nearly all 

 ol these qualities and appointments and it behooved the designers of the 

 new building to take advantage of modern materials and mechanical 

 resources and devise the best possible system of shelving and mechan- 

 ism to meet all the requirements. This was quite successfully accom- 

 plished. Having prepared the courts of the building and the walls of the 



